A deadbolt lock is equipped, in most cases, with a rectangular solid bolt. The bolt of a deadbolt lock is not extendible to lock until aligned with a bolt recess, i.e., behind a jamb, a notch in a bolt-work, or an opening in a strike or other similar unobstructed volume of space into which the bolt may extend.
In order to close a security container and lock a dial combination lock, such as a Mas-Hamilton X-07 or a Mas-Hamilton Auditcon series combination lock to secure the container, it is necessary to first close the container upon which the lock is mounted, and thereafter to extend the bolt by manually rotating a dial knob or control while the bolt is aligned with a recess or void space, thereby permitting its extension. Due to the rectangular solid structure of the bolt, the container cannot be closed with the bolt extended; and if not extended after closing, the container remains insecure. The Mas-Hamilton X-07 and Auditcon locks are available from the Mas-Hamilton Group, Lexington, Ky.
In environments where there is required frequent access to the container such as a safe, for instance, in retail stores, fast food restaurants, and businesses with a high-volume of cash business employees tend to leave the lock unlocked between accesses in order to reduce or eliminate the nuisance of opening the lock or having to locate a person with the lock combination for each opening or access. The door to the safe may be closed, but the lock is not relocked in such a manner that the safe is secure. This leaves the contents of the container available for pilferage or theft. There are many other environments where it is desirable to automatically lock the container upon closing while having the advantage of the bolt configured as a deadbolt.
An auto-locking device, capable of use in conjunction with a dial combination lock to automatically lock upon the door carrying the lock closing and engaging a strike, is variously marketed under the designation of LM5100 by Lockmasters of Nicholasville, Ky.; the Model 8475 marketed by Sargent and Greenleaf of Nicholasville, Ky.; and the CDX-07 electronic combination lock marketed by the Mas-Hamilton Group of Lexington, Ky. An example of the mechanism of the LM5100 is illustrated in U.S. Pat. No. 5,257,519. The mechanisms of the Sargent and Greenleaf 8475 and the Mas-Hamilton Group CDX-07 lock also incorporate a spring-biased bolt and a triggering device outside the spring-biased bolt to release the spring-biased bolt.
Disadvantages of the LM5100 and both the other automatic locking devices identified above are that use of such a device requires an installation of the device and the lock on the interior of the container door such that these devices do not lend themselves to merely replacing the combination lock previously installed. The need for new holes to be drilled in the container door leaves the previous holes as a possible source of vulnerability to the container, and these devices require a second locking device with a combination lock in order to accomplish the desired function. The Lockmasters LM5100, Sargent & Greenleaf Model 8475 and the Mas-Hamilton CDX-07 locks all require the lock bolt to be extended in order for the lock to lock the door, thereby blocking the spring-biased bolt to ensure that the container is locked and secure; otherwise, the spring-biased bolts may be subject to being dislocated and the container or room opened. The extending of the lock bolt requires the rotation of the lock knob or dial.